1. Field of Invention
The present invention relates, generally, to a golf club head and, more specifically, to a golf club head with a face made from a titanium alloy.
2. Discussion of the Background
When a golf club strikes a golf ball at rest, the ball is propelled at high speed from the tee to the landing area. Thus, the kinetic energy of the moving club head is converted to kinetic energy in the moving golf ball. The golf ball is only in contact with the face of the golf club for a few millionths of a second during impact and the distance achieved by the golf ball is a result of the combination of the initial velocity of the ball after impact, the launch angle, and the spin of the ball. Generally, however, the greater the velocity of the ball after impact, the farther the ball will travel.
The mass of the club head and the velocity at impact combine to determine the initial velocity of the golf ball after impact. However, not all of the energy transferred to the ball is converted to kinetic energy and manifested as velocity. Some of the energy manifests as heat in the ball. Much of the kinetic energy lost as heat is related to the viscoelastic response of the ball during deformation.
The present invention is, in part, a result of the discovery that a golf club face that deforms in preference to the ball will, unless it is a lossy viscoelastomer, generally have a smaller hysteresis loop on deformation and, therefore, result in less energy loss. In addition, it has been found that it is preferable that the face of the club head deform more than the remainder of the club head body. Thus, controlling deformation of the golf club head in preference to deformation of the golf ball will result in the golf ball traveling farther.
Generally, a golf club comprises a shaft portion, a head portion, and a grip portion. The part of the golf club head portion that comprises the hitting surface is referred to as the golf club “face”. Generally, a golf club face abuts or is adjacent to both a top wall (or crown) of the club head and a bottom wall (or sole) of the club head.
Most “woods”, such as the driver and the fairway woods, are in the form of a hollow shell (or perhaps filled with foam), usually of metal. Because only the best and strongest golfers can effectively swing a driver head that weighs more than 220 grams, the maximum weight of the club head is essentially a design constraint of the club head. Further, when the front side of the face of the golf club head strikes a golf ball, extremely large impact forces are produced potentially causing cracking and/or material failure. Thus, the golf club face portion must be structurally adequate to withstand large repeated forces, such as those associated with ball impact. In addition, a large club head face is highly desirable because it strongly reduces the percentage of errant hits.
Thus, there are contrasting design considerations when designing a golf club head—the desirability of a light club head, but with a large club face and a club head that is durable enough to withstand repeated striking of the ball. One method of increasing the durability of the club head is to add additional material (e.g., steel or titanium) to thicken the club face or to add ribs to the club face. However, the designer cannot simply add additional material to strengthen the face indiscriminately because doing so also increases the overall weight of the club head, which is undesirable.
Prior golf club heads typically had relatively thick faces, which would deform only slightly at impact thereby causing the golf ball to deform, which created a significant loss of kinetic energy through conversion of heat in the ball.
Thus, there is a need for a new golf club head with a club face structure providing enhanced deformation for improving club performance, and that has structural integrity, thereby reducing cracking and material failure, without otherwise adversely affecting club performance, look, and feel; and with limited affect on club head weight.